Field of the Invention
The invention relates to a bidirectional Metal-Oxide-Semiconductor (MOS) device and a method for preparing the same.
Description of the Related Art
As shown in FIGS. 1-2, conventional bidirectional MOS devices share one drift region (N-type well) to reduce the length of the drift region. However, the blockage of any one of the devices tends to result in transverse or longitudinal breakdown. In order to solve the breakdown problem, the length of the drift region of the devices must be increased, as a result, the size of the devices, the resistance of the drift region, and the doping dosage in the drift region are increased. Thus, the conventional bidirectional MOS devices have big size and large resistance of the drift region. This reduces the performance of the MOS devices.